Was invented in 1880 by an American, Colonel Henry Steele
Olcott. The horizontal bars signify peace and harmony between
all races
throughout the world while the vertical bars represent
eternal peace within the world.

Blue:
signifying the concept of loving kindness and peace in Buddhism.
Yellow: signifying the Middle Path, that is, the complete
absence of form and emptiness. Red: signifying achievement,
wisdom, virtue, fortune and dignity. White: signifying
purity, emancipation, that the Dharma will always exist regardless
of time or space. Orange: the essence of Buddhism
which is full of wisdom, strength and dignity. The combination
of these five colours symbolizes the one Truth.